Theoretical understanding of quantum cascade lasers (1994-97).
Principal collaborator: Vera Gorfinkel
The quantum cascade laser (QCL) is a new mid-infrared laser, based on unipolar transitions of electrons between energy levels created by quantum confinement. I became involved in the QCL research at an early stage [ US Pat. 5,457,709 ] shortly after the first demonstration of the device at Bell Laboratories. Recently, we carried out a theoretical analysis of the QCL operation which showed that it was dominated by hot-electron effects. These effects arise from the power dissipated in each cascade period, mainly due to nonradiative electron transitions. The energy stored in the transverse degrees of freedom, corresponding to in-plane motion of carriers, fundamentally changes both the lineshape of intersubband resonance and the spectral characteristics of gain. Our work has shown that the QCL has an enormous reserve for improvement and identified new development strategies.
Key papers: 139, 145 [ on-line # 146.html ] [ download # 146.ps ]
Where the numbers refer to the attached list of Publications
Theoretical studies of QCL issues continues in my group,
see e.g. paper # 148 [Kisin et al, J. Appl. Phys., 82, 2031-2038 (1997)]
[ download PDF (full paper, 180K) ]
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